Diagnostic Aids

When attempting to diagnose an intermittent problem, use scan tester to review supplemental diagnostic information. Supplemental data (scan tester MALF HISTORY) can be used to help duplicate an intermittent problem. Using Diagnostic Service Probe (12092782) allows voltage to be read on wires without disconnecting connectors.

If MALF history indicates a Code 26 was set with Code 32 and no other Quad Driver related symptoms exist, Code 32 was probably set due to a problem in circuit No. 697, the linear EGR module or possibly the PCM.

If just Code 32 is set, check desired and actual pintle position. If both parameters have a percent open value in them, but they do not closely match each other, sensor may be sticking.

Fig 1: Code 32 Schematic EGR System Error

Fig 2: Code 32 Diagnostic Flow Chart - 1 Of 3 EGR System Error

NOTE: Test numbers refer to numbers on diagnostic chart.

If only Code 32 is set, problem is in the position feedback portion of the system. Since the valve is turned off at idle, or with ignition on, the voltage reading should be 0.3-1.2 volts. If viewing desired or actual position in Tech 1 fuel and emission table, zero percent should be indicated during this step.
Code may have set during the previous step due to a position feedback sensor being struck at some voltage level or due to the EGR module commanding the valve partially open. This step will determine if fault is in module or valve. This step will result in a Code 26 and should be ignored.
If engine is running rough or will not idle, it may be due to EGR being on, which is also indicated by the pintle voltage being greater than 4 volts.

Fig 3: Code 32 Diagnostic Flow Chart - 2 Of 3 EGR System Error

NOTE: Test numbers refer to numbers on diagnostic chart.
This chart assumes that Codes 26 and 32 were related; therefore, it is important that other Quad Driver related functions are operating properly before diagnosing potential EGR problems. If there is a Quad Driver problem, data in the Tech 1 general information table will indicate the problem is related to QDM A or QDM B.
When engine is at idle, EGR is commanded off. During this condition, linear EGR module should be supplying 12 volts to PCM pin J2A05. If Codes 26 and 27 are set, problem is due to a low voltage being detected on circuit No. 697.
A blown EGR fuse would result in a Code 26 due to the low voltage on circuit No. 697.

Fig 4: Code 32 Diagnostic Flow Chart - 3 Of 3 EGR System Error